1. Field of the Invention
The present disclosure relates to a signal conversion method for a display image, and more particularly, a signal conversion method for a display image in the application of a wide-color-gamut display.
2. Description of Related Art
As electronic technology advances, outdoor use of display apparatuses has been increased; and under strong outdoor lighting, display apparatuses are required to provide higher luminance for users to view the display screen clearly. Therefore, in order to improve transmittance of the display panel, the practice of adding brightness (W) sub-pixels to a liquid crystal display of three primary colors (R, G, B) is a solution that has recently received widespread attentions. The brightness sub-pixels being added into the RGBW liquid crystal display have very high transmittance, and thus may significantly improve the transmittance of the liquid crystal panel. When the display screen is full bright, luminance is nearly doubled, and power consumption is also relatively lowered. When the product is used outdoor, due to its high luminance characteristic, the user may also view clearer images. However, when the RGBW liquid crystal display simultaneously displays pure colors and white screen, R, G and B sub-pixels, due to having areas less than that of the RGB liquid crystal display of the same resolution, may cause the brightness of the pure colors to become dark, and thereby may appear to have a poor quality in human eyes.
The introduction of wide-color-gamut panel technology may other be another feasible technical solution. The wide-color-gamut panel may increase a color gamut value of the existing National Television System Committee (NTSC) from 72% to approximately above 90% and use the NTSC's characteristic of high color gamut value to improve the pure color screen problem of the RGBW display. However, color resistance in the color filter adopted by the conventional wide-color-gamut liquid crystal display may lower the transmittance, and luminous efficiency of the multi-wavelength backlight module adopted by the wide-color-gamut liquid crystal display is low, such that these two factors would both lead to an increase in power consumption.
The two technologies described in above each have its own advantages and disadvantages that can be complemented, and thus it is very desirable to develop and integrate a RGBW conversion and a wide-color-gamut color integration algorithm. Computation process of the existing RGB to RGBW conversion algorithm is very complicated, thereby causing the computation speed under a high resolution screen to be very slow.